The present invention relates to a floor structure for reducing vibrations caused by, for example, an earthquake or a device mounted on the floor.
The recent advancement in scientific technology particularly in the field of electronics has offered various kinds of precision instruments such as a computer, telecommunication equipment and the like which, due to precision thereof, require that no intense vibration be transmitted thereto. Those precision machines are often installed in a tower building which, however, is not designed to prevent transmission of vibrations to upper floors thereof when an earthquake occurs. Therefore, it is absolutely necessary to provide a means for reducing the vibration transmitted to those machines thereby to protect the latter.
Also, there have been used recently, various devices that themselves create vibrations, and some of such devices are used even in the offices. It is advantageous to prevent the vibration caused by such devices from spreading.
For reducing or damping the vibration transmitted between the floor and the precision machines or the vibration creating devices, a structure has been hitherto employed in which each of the machines or devices is elastically supported by elastic means such as coil springs which are in turn fixed at lower ends thereof to the floor. However, the floor has in many cases dual slabs to provide, between a lower slab and upper slab or base floor, a space for arranging pipes and complicated wiring of the machines, and it is the lower slab to which the support springs are fixed in order to avoid considerable reinforcement to stanchions which support the base floor. Therefore, after the machines or devices are arranged in a room, rearrangement thereof necessitates an alteration and repair of the base floor and is thus inconvenient.
Furthermore, an earthquake usually involves vibration in both vertical and lateral directions, and some of the devices also creates such vibration. The known structure of the above type can not effectively protect the machines from such nonuniform vibration, particularly from the lateral vibration.
Accordingly, an object of the present invention is to provide a floor structure for reducing the vibration and which permits arrangement and rearrangement of machines or devices supported by the floor structure without substantial alteration and repair of a preconstructed floor of a building or other construction.
Another object of the present invention is to provide a floor structure which may reduce or damp vibration in both vertical and lateral directions thereby to protect machines from such nonuniform vibration.
A further object of the present invention is the provision of a floor structure which is simple and may be manufactured at low cost.